Editorial Commentary: The Quest to Prevent Knee Anterior Cruciate Ligament Bone Tunnel Widening Continues.

The exploration of methods to improve healing of a tendon graft in a bone tunnel in anterior cruciate ligament reconstruction has been a subject of basic and translational research for over 30 years. It is well recognized that the graft attachment site to the bone represents the "weak link" in the early healing period. We as clinicians search for methods to augment healing of the tendon graft in the bone tunnel. Agents and techniques that improve osteoinduction may improve healing. Implanted chondrocytes may promote tendon-to-bone healing by participating in new bone formation or, alternatively, by providing signaling molecules that stimulate local or distant endogenous cells. Tracking of cell fate after implantation will be required to further delineate biologic mechanisms.